code: def _get_chunk_index_from_index(self, index: int) -> int:
      return self._reader._get_chunk_index_from_index(index)
  
imports: import logging
  import os
  from dataclasses import dataclass
  from typing import Any, Dict, List, Optional, Tuple, Union
  from lightning.data.streaming.constants import _INDEX_FILENAME, _LIGHTNING_CLOUD_LATEST, _TORCH_GREATER_EQUAL_2_1_0
  from lightning.data.streaming.item_loader import BaseItemLoader
  from lightning.data.streaming.reader import BinaryReader
  from lightning.data.streaming.sampler import ChunkedIndex
  from lightning.data.streaming.serializers import Serializer
  from lightning.data.streaming.writer import BinaryWriter
  from lightning.data.utilities.env import _DistributedEnv, _WorkerEnv
  from lightning.data.utilities.format import _convert_bytes_to_int
label_desc: Use image node_id 15 for calling the Cache obj's underlying member method code with example usage: obj._get_chunk_index_from_index(index) and returns: self